It might be just a remote UI over "Windows Cloud Eternal" at that point but if by then we've moved to "Apple Forever OS" or "The Eternal Year of the Linux Desktop" I'll make a balanced diet out of hats
Honestly, a Phone/Dex style thin client that you connect to a bigger screen and that remotes into Windows Cloud Eternal seems like a solid sale for them
They sell you compute, plus a phone that gets renewed every 2-5 Years